Physico-chemical characterization of ferric exchanged y zeolites

Ferric exchanged Y zeolites are prepared by ion exchange and are characterized by X-ray diffraction, thermal analysis, IR and visible spectroscopy. The number of hexa-aquo complexes, [Fe(OH)(H₂O)₅]²⁺, in supercages is determined from thermal analysis, and cation distribution at different sites is discussed. The visible spectra confirmed the formation of hexa-aquo complexes of iron in freshly prepared hydrated FeNaY zeolites. The migragtion of ferric ions from the supercage to the sodalite cage or hexagonal prism takes place on activation of Fe³⁺Y zeolites at 500°C for 2–10 h. The thermal stability of the activated samples is discussed on the basis of X-ray and thermal analysis.